BLE RGB LED Board

flux

Routing was partially completed: the D1→D32 LED data chain is routed, plus several support/control nets including level-shifter LED data, charger ISET/ILIM/TMR, BAT_NTC, CHG_STAT_N, and USB-C CC/ESD connections.
Open items:
  • The board is not fabrication-ready yet.
  • 88 airwire issues remain, mainly power distribution and blocked control/debug routes.
  • The compact charger/battery/power area needs either a full-board autorouter pass or small placement cleanup.
  • Key unrouted items include BAT_PLUS, VBUS, SYS, LED_VDD, 3V3/GND strategy, LED_EN, RESET_N, PGOOD_N, SWD reroute, USB D+/D− reserved ESD lines, and antenna-related copper details.
  • I updated Layout Plan with the partial routing status.
Suggested next steps:
  1. Slightly spread U2/J2/U5/U3 power area and rerun routing.
  2. Route power with wider copper/pours rather than skinny traces.
  3. Re-route SWD/reset cleanly.
  4. Run full DRC after the next routing pass.
S

sullys

keep working til it's finished please

flux

I’ll keep going: first I’ll open up the congested power/charger area, then continue routing remaining power, debug, reset, and status nets, with checks after each cleanup pass.

flux

I’m blocked now because the account has no available ACUs, so I can’t continue executing layout/routing actions.
Accomplished in this session:
  • Re-checked the routing state and confirmed the main blocker is still the tight charger/battery area around U2/J2.
  • Removed leftover conflicting SWD trace segments that were causing copper-overlap problems.
  • Expanded the board from 80×40 mm to 90×42 mm to improve routing space and reduce density.
Open items:
  • Re-place/spread U2, J2, R5/R7/R8/R9, U3, U5, and nearby passives into the new extra space.
  • Continue routing remaining airwires, especially BAT_PLUS, VBUS, SYS, LED_VDD, 3V3/GND, LED_EN, RESET_N, PGOOD_N, SWD, and USB D+/D− reserved/ESD lines.
  • Run DRC after routing and clean any remaining conflicts.
  • Update the Layout Plan after the next completed routing pass.
Check ACUs
List routing blockers
Suggest charger placement
Run DRC
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Files

Schematic

Layout

Preview

Power and Runtime Notes — BLE RGB LED Display
Summary
The board can be compact, but battery life depends almost entirely on average LED current. Firmware current limiting is required; a thin LiPo cannot safely support sustained full-white display current unless the selected pack and connector are rated for it.
Power Tree
Diagram



  
    
  
  
    
  




















USB-C VBUS 5 V
BQ24074 charger/power path
1-cell LiPo BAT_PLUS
SYS rail
TPS78233 3.3 V
ANNA-B112 BLE module
SN74LVC1T45 3.3 V side
MP5075 LED switch
LED_VDD
32x SK6812MINI-E
Estimated Load Modes

Table

ModeBLE/3.3 V railLED railApprox. total loadNotes
Sleep / storageµA to low mAOffVery lowDepends on firmware sleep and charger/load-switch leakage.
BLE advertising, LEDs offlow mAOfflow mABest long-runtime mode.
Low brightness animationlow mA50-150 mA50-170 mARecommended normal operating range for thin cells.
Medium brightness animationlow mA250-500 mA250-520 mACheck battery, connector, copper temperature.
Worst-case full whitelow mAup to ~1.9 A~1.9 A+Avoid sustained use unless every power-path element is rated and tested.
Key Limits and Risks
  • SK6812MINI-E worst-case budgeting is commonly about 60 mA per RGB pixel at full white; 32 pixels can approach about 1.9 A.
  • J2 Molex 78171-0003 is rated about 1.5 A, so a full-white display can exceed connector capability.
  • MP5075 is useful as a load switch/short protection device, but it should not be treated as a precise LED current limiter for a thin battery.
  • LED_VDD follows SYS/BAT behavior and can fall outside guaranteed LED operating range as the LiPo discharges.
  • Firmware must reduce brightness or disable LED_EN near low battery under load.
Charger Configuration Notes
  • BQ24074 supports single-cell LiPo/Li-ion charging and power-path operation.
  • Charge current and input current are configured by resistors in the schematic; verify actual fitted values before release.
  • Charging while LEDs are active may reduce charge current or trigger DPPM/thermal regulation.
Runtime Examples
Approximate runtime using usable battery capacity only:

Table

BatteryAverage board currentApprox. runtime
300 mAh50 mA~6 h
300 mAh150 mA~2 h
500 mAh50 mA~10 h
500 mAh150 mA~3.3 h
1000 mAh50 mA~20 h
1000 mAh150 mA~6.7 h
Actual runtime will be lower with regulator losses, cold cells, aging, LED color mix, and conservative low-battery cutoff.
Firmware Power Policy
  1. Boot with LED_EN off.
  2. Read battery voltage before enabling LEDs.
  3. Enable LEDs at a low brightness cap.
  4. Re-measure battery voltage under LED load.
  5. Apply global brightness/current limiting.
  6. Shut off LED_EN with hysteresis before LEDs become unreliable or the battery is over-discharged.
  7. Keep sustained full-white patterns disabled or time-limited.
Battery Pack Requirements
Use only an approved protected 1-cell LiPo pack with:
  • 4.2 V maximum charge voltage.
  • Overcharge, overdischarge, overcurrent, and short-circuit protection.
  • Discharge rating greater than the firmware/hardware current limit.
  • Compatible 10 kΩ-class NTC behavior for BQ24074 TS input.
  • Verified J2 pinout: BAT_PLUS, BAT_NTC, GND.
  • Certified transport/safety documentation as appropriate.
Open Decisions
  • Exact battery capacity, thickness, supplier, connector polarity, and NTC curve.
  • Whether to add a stricter hardware current limiter/eFuse for LED_VDD.
  • Final low-battery cutoff threshold under LED load.

  • Summary

  • Power Tree

  • Estimated Load Modes

  • Key Limits and Risks

  • Charger Configuration Notes

  • Runtime Examples

  • Firmware Power Policy

  • Battery Pack Requirements

  • Open Decisions